fix(updater): treat GitHub releases 404 as no update

GitHub returns HTTP 404 for /releases/latest when no release exists.
Previously this logged at INFO and emitted failed; now return None so
check completes as up-to-date and cooldown applies.

Made-with: Cursor

Author: richardkoehler

src/dbs_annotator/utils/updater.py

@@ -117,8 +117,19 @@ def _fetch_latest_release(self) -> ReleaseInfo | None:
                 "User-Agent": f"DBSAnnotator/{self._current_version}",
             },
         )
-        with urllib.request.urlopen(request, timeout=self._timeout) as response:
-            payload = json.loads(response.read().decode("utf-8"))
+        try:
+            with urllib.request.urlopen(request, timeout=self._timeout) as response:
+                payload = json.loads(response.read().decode("utf-8"))
+        except urllib.error.HTTPError as exc:
+            # GitHub returns 404 when repo has no published releases (or repo missing).
+            if exc.code == 404:
+                logger.debug(
+                    "No GitHub releases/latest for %s (HTTP %s); treat as no update",
+                    self._repo,
+                    exc.code,
+                )
+                return None
+            raise
 
         tag = str(payload.get("tag_name", ""))
         if not tag:

tests/unit/test_updater.py

@@ -0,0 +1,44 @@
+"""Tests for :mod:`dbs_annotator.utils.updater`."""
+
+from __future__ import annotations
+
+import io
+import urllib.error
+from unittest.mock import patch
+
+import pytest
+
+from dbs_annotator.utils.updater import _CheckSignals, _CheckWorker
+
+
+def test_fetch_latest_release_http_404_returns_none() -> None:
+    """GitHub ``/releases/latest`` → 404 when nothing published; no exception."""
+    signals = _CheckSignals()
+    worker = _CheckWorker("owner/repo", "1.0.0", 10.0, signals)
+    err = urllib.error.HTTPError(
+        "https://api.github.com/repos/owner/repo/releases/latest",
+        404,
+        "Not Found",
+        {},
+        io.BytesIO(b""),
+    )
+    with patch("urllib.request.urlopen", side_effect=err):
+        assert worker._fetch_latest_release() is None
+
+
+@pytest.mark.parametrize("code", [403, 500, 502])
+def test_fetch_latest_release_other_http_raises(code: int) -> None:
+    signals = _CheckSignals()
+    worker = _CheckWorker("owner/repo", "1.0.0", 10.0, signals)
+    err = urllib.error.HTTPError(
+        "https://example.com",
+        code,
+        "err",
+        {},
+        io.BytesIO(b""),
+    )
+    with patch("urllib.request.urlopen", side_effect=err), pytest.raises(
+        urllib.error.HTTPError
+    ) as ctx:
+        worker._fetch_latest_release()
+    assert ctx.value.code == code